结构光三维测量技术具有快速、无损接触、重复性好等特点, 被广泛应用在模具检测及工程制造中, 但传统投影式结构具有离焦模糊的缺点。本文采用全视场外差干涉的原理, 使用高精度声光移频外差干涉条纹代替传统光栅投影中的编码条纹, 与传统工业相机结合使用便可获取快速的全视场三维数据。根据对系统参数的建模计算, 设计加工了外差干涉三维测量仪, 联合使用电动平台及棋盘格标定板来获取该系统的相位高度映射模型, 最后对标准陶瓷台阶进行了测量。实验结果复现了原物体的三维形貌及高度信息, 在30°的观测角下系统的高度分辨率为22 μm, 视场内的空间分辨率优于58 μm, 测量标准陶瓷平板, 高度误差为75 μm。该方法具有检测速度快、体积紧凑、抗环境干扰性强等特点。

Three-dimensional measurement technology based on structured light is characterized by speed, non-destructive contact, and good repeatability. In contrast, although traditional projection systems are widely used in mold inspection and engineering manufacturing, they have the disadvantage of defocusing. In this study, the principle of heterodyne interferometry was applied, and heterodyne interferometric fringes replaced coding fringes in a traditional grating projection. An industrial camera was used as it can acquire full-field three-dimensional data quickly. In accordance with the calculation of system parameters, a three-dimensional measurement system based on heterodyne interferometry was designed and manufactured. A phase-to-height model was first acquired using an electric moving stage and checkboard. Then, a standard ceramic plate was measured. Experimental results show that the three-dimensional shape and height information of a measured object can be successfully recovered using the developed system. The height resolution of this system achieves 22 μm at an observation angle of 30°; furthermore, the space resolution in the field of view exceeds 58 μm. Height error in the measurement of the standard ceramic plate is 75 μm. The developed system has the characteristics of high detection speed, compact volume, and insensitivity to environmental disturbances.